This invention relates to the use of gelatin in sheets as image support and to a method for the transfer thereof to 3-D surfaces or bodies.
Gelatin is a protein derived from animal skin, fibrous white connective tissue and bones. This protein is fully composed of amino acids in polypeptide linkages and is derived by boiling bones, tendons, ligaments etc. in water. Gelatin is now obtained with industrial processes which guarantee its necessarily safe production. Basically, obtaining gelatin with industrial processes consists in extracting collagen from ox or pig skins which have been previously submitted to a thorough washing, purifying and drying process.
The uses of gelatin are known in food sector being present in that case as dry gelatin. Examples of use of dry gelatin are for preparing desserts, meat products (canned ham, meat slices, cooked meat, etc.), pastry products, soups, ice-creams, etc. In this case, gelatin must be used unmixed, when it is transparent, tasteless and odourless.
Another use currently known of gelatin is in the field of photography. The fact that gelatin is a medium significantly effective as protecting colloid for silver chloride dispersed therein prevents silver salt to be separated. In addition, gelatin shows a great easiness to be insolubilized with titanium which makes it a basic element for preparing silver salt sensitive films and photographic paper. In addition to regulating silver halide grain, gelatin has the property to indirectly controlling the photographic properties because of the presence of impurity in the different types of gelatin which act as restringent, sensitizer or desensitizer. For preparing plates and films, gelatin must have a great elasticity, a low content of ashes and a 5-6 pH with a 10% moisture content.
In addition, gelatin is also used in the pharmaceutical field, for example for producing capsules, either soft or hard, as binding agent for producing tablets and sugar-coated pills, for producing suppositories, pills and preparing emulsions. Gelatin is capable to protect drugs against air and light influence. The use of gelatin is also known as a substitute for blood plasma and as haemostatic sponges because they show a perfect compatibility with human tissues. In this case, a special kind of gelatin is used which has to be pyrogen-free.
In the chemical industry, gelatins are used which require a colloid protector for particle size control processes, namely to prevent separating steps or to assist in clarification processes.
The state of the art includes other uses of gelatin such as the production of adhesives, cements, plastics, artificial silk, moulds and applications in the field of bacteriology to prepare culture broth. In addition, gelatin is also widely used in paper and textile industries.
GB 323 724 (Steele) relates to transfers for decorative purposes comprising a paper backing, a first layer of soluble gelatin and a second layer of permanent gelatin. In use, an image is printed onto the layer of permanent gelatin which is then adhered to the surface of an article, such as a glass table top or a window. The application of heat and/or moister dissolves the layer of soluble gelatin and permits the paper backing to be removed.
The present invention differ from the teaching of said prior art in that there is no paper backing during image transfer, i.e. the gelatin sheet is self supporting.
FR 2640473 (Phoughon) relates to the food industry and to a product for decorating savoury or sweet culinary preparations, said product having the form of a film of an edible substance including decorations which are themselves edible. The film advantageously consists of at least one of the materials from the group of materials comprising communion wafers, almond paste, chocolate and gelatine. In the case of the film being of gelatine this is not at all self/supporting as in the present invention but two auxiliary protective and supporting films are used. Moreover the group of cited materials does not share the property of being elastic, as is essential to the gelatine used as in this invention but only edible.
JP-53135717 (SUMITOMO BAKELITE CO.)discloses the application of a water-soluble edible printed film such as a gelatin/starch system to food, dissolving film to leave image and cooling. The film are placed dried onto the surface of edible matter of high water content in heat fused state, dissolving the film alone by water and heat. Therefore said films are not at all elastic in the moment to be placed onto the product on which they have to leave an image.